Or in space. It's pointless. Why spend trillions when you can spend a few billion for the same capacity and without violating nuclear weapons treaties or devising new weapons (I don't think that current weapons can be used due to the way that they are built).

Although I agree that it isn't likely to ever be built, the only thing I've ever seen that may be possible with todays technology can match or exceed the capacity of an Orion based drive would be another nuclear rocket.

No chemical based rocket can even come close to the capacity of a nuclear drive, even one as brute force and inefficient as an Orion. The 1,000 ton payload was the very low end for these designs they were talking about about designing ships upwards of 10,000 tons. Additionally that 1,000 tons of payload would have been the payload to Mars, Jupiter or Saturn, along with enough nuclear bombs to get home. Even something like the Sea Dragon with its 500 ton capacity isn't going to get all of that 500 tons delivered to a destination such as Mars. Building clean nuclear bombs and a launch platform that would throw less radioactive material into the atmosphere than a typical coal 1000 megawatt power plant may involve nothing more than dusting off and implementing plans of existing nuclear bombs designs. Considering the very nature of the Orion concept I really doubt that building one would cost anywhere near 'trillions'. In fact if NASA and their voodoo accountants can be kept away from the project I doubt the ship itsell would cost more than a typical aircraft carrier if built by the right people ie: not Lockheed Martin.

Though it makes some sense, I agree that there are better optoins than recreating a Saturn 5.

The cancellation of the Saturn-5 was a mistake, but that does not mean we have to re-create it more than 30 years later.

The Saturn 5 option or a derived rocket: Most of the plans and the information still exists. When the Saturn-5 was cancelled, they even had an upgraded F-1 engine tested and ready to be used. It is still a valid engine despite that modern technology may dictate some modifications. Using the existing plans for a new engine would cut development costs.
However, it is not a bad idea to redesign the rest of the rocket with modern materials in mind. The gain in weight is surely significant enough to do this.

Right after the Challenger-accident some NASA already revived this idea: Use the upgraded F-1 for a new rocket: They called it the "Jarvis". (Gregory Jarvis one of the 2 "civilians" on board of the Challenger. The other "civilian" was Sharon Christa McAuliffe. Jarvis worked for Hughes and was considered the unluckiest guy since he was mentioned for at least 6 other previous flights before he was finally allowed to fly. )

Alternatives :- The Russian Energya rocket (plans and materials still exist). It is even more powerful than the Saturn.
No development cost and limited time needed to produce.

- Use the Shuttle-C option. The US spent already enough dollars to study this option. The hardware exists; According to some NASA people all they have to do is "putting the thing together". Furthermore, the remaining shuttles could even benefit from this and since so far, there is no other alternative for these shuttles, we should not stop its development.
Moderate development cost and estimated time needed to produce.

- An entirely new vehicle.
Lots of time needed for research, some time and political influence to decide about what option to use, some more development and test time and an unknown time needed to produce.

Or in space. It's pointless. Why spend trillions when you can spend a few billion for the same capacity and without violating nuclear weapons treaties or devising new weapons (I don't think that current weapons can be used due to the way that they are built).

Although I agree that it isn't likely to ever be built, the only thing I've ever seen that may be possible with todays technology can match or exceed the capacity of an Orion based drive would be another nuclear rocket.

No chemical based rocket can even come close to the capacity of a nuclear drive, even one as brute force and inefficient as an Orion. The 1,000 ton payload was the very low end for these designs they were talking about about designing ships upwards of 10,000 tons. Additionally that 1,000 tons of payload would have been the payload to Mars, Jupiter or Saturn, along with enough nuclear bombs to get home. Even something like the Sea Dragon with its 500 ton capacity isn't going to get all of that 500 tons delivered to a destination such as Mars. Building clean nuclear bombs and a launch platform that would throw less radioactive material into the atmosphere than a typical coal 1000 megawatt power plant may involve nothing more than dusting off and implementing plans of existing nuclear bombs designs. Considering the very nature of the Orion concept I really doubt that building one would cost anywhere near 'trillions'. In fact if NASA and their voodoo accountants can be kept away from the project I doubt the ship itsell would cost more than a typical aircraft carrier if built by the right people ie: not Lockheed Martin.

If "bringing lots of material into space" is the only goal, without any other considerations, the nuclear drive is the thing to go for, but on a longer term there are other options. The space elevator for instance.

Furthermore, the remaining shuttles could even benefit from this and since so far, there is no other alternative for these shuttles

There's the great alternative of putting them in museums. I've no problems with a Shuttle-C but I honestly believe that the Shuttles themselves should never fly again.

I agree with whoever said it'd be pretty easy to put together and while that's flying either a new heavy lift rocket should be built or all heavy lift rocket work should be put on hold while alternatives are looked into. Ten years of work should provide enough know how to decide if JP Aerospace's 'Airship to Orbit', the space elevator, laser launch ships or a gas gun launch system or something else can be used for large amounts of cargo. Existing boosters such as the EELV should be adapted for manned capsule launches.

In stead of a space elevator that goes all the way down to earth, we could build already now, a space elevator that starts in LEO and goes up beyond GEO. The difference is that in stead of strength of nanotubes and required nanotechnology, a rigid structure is needed to bring up payloads from LEO to whatever orbit or beyond. In stead of nanotubes a relatively small and light steel rail would do the job. The whole stuff could be powered by solar cells (for powering the maglev) and some small thrusters could keep the thing in place.

Could be started now. Each Shuttle can bring approximatively 50 km of rail in orbit. Something like 750 shuttle flights or 175 Energya (shuttle-c ?) flights needed. Alternatively this structure can be build on the moon and catapulted into space

Furthermore, the remaining shuttles could even benefit from this and since so far, there is no other alternative for these shuttles

There's the great alternative of putting them in museums. I've no problems with a Shuttle-C but I honestly believe that the Shuttles themselves should never fly again.

I agree with whoever said it'd be pretty easy to put together and while that's flying either a new heavy lift rocket should be built or all heavy lift rocket work should be put on hold while alternatives are looked into. Ten years of work should provide enough know how to decide if JP Aerospace's 'Airship to Orbit', the space elevator, laser launch ships or a gas gun launch system or something else can be used for large amounts of cargo. Existing boosters such as the EELV should be adapted for manned capsule launches.

I agree that it would have been better to have separate vehicles to bring people and heavy payloads in space. But so far, all the US has got to bring people into space is the space shuttle. Keeping the shuttles grounded means that the small Soyuz is the only way to bring astronauts to the ISS, which becomes the only work-environment in space.
Grounding the shuttle may mean re-making the same mistake as canceling the X-20, the Apollo & Saturn-5 and several other projects.

What, out of a interplanetary spacecraft, really needs to be sent up all at the same time?

I mean, do large ocean-going ships get assembled in a factory and then put on wheels and delivered to the sea from a factory in Illinois? Not really, the ship is designed to be in the water, so it's assembled right next to a harbor and tossed in the drink when mostly complete. Big things are built in place.

So why are most things in space either constrained to fit on top of a single launch vehicle or have a long drawn-out assembley process?

Well, because every second of human time in space has a pretty high price, robotic technology is only so good, and it's so damn expensive to launch anything big anyway.

If you think about it, the first reason reduces back to the third. Why is it so expensive to be in space? Because you have to spend a lot of money to build an extra-lightweight vehicle and send it up and down many times each year. The consumables for a spacewalk are only a little bit more expensive than those for scuba diving, if you want to draw random unsubstantiated allegations. Plus you can always build your large structure inside of an inflated bubble.

Really, the only big metric is cost per pound for a reasonable amount of payload to a location in orbit. We don't *need* a Saturn V to go places.

No, but how much cheaper would it have been to use a SeaDragon (just because I love the idea of that rocket) to send the ISS into space? Wouldn't need such small modules anymore, and really, I think that's the point of mega-lift vehicles. With a mega-lift vehicle you can send a decently sized module into space, large enough that it can be divided into fairly room sections. Do that, and you can get a real hotel.

I mean, do large ocean-going ships get assembled in a factory and then put on wheels and delivered to the sea from a factory in Illinois? Not really, the ship is designed to be in the water, so it's assembled right next to a harbor and tossed in the drink when mostly complete. Big things are built in place.

Really, the only big metric is cost per pound for a reasonable amount of payload to a location in orbit. We don't *need* a Saturn V to go places.

There currently is no 'need' for one but a really large vehicle should be able to drive launch costs down. If the cost per pound lowers enough there will be an explosion in space development. A really large booster could very well help accelerate that happening.

How many large ocean-going ships ever stayed where they were assembled? A large capacity launch platform will be doing basically the same job as most really large ocean-going ships, moving large amounts of cargo from one place to another.

There currently is no 'need' for one but a really large vehicle should be able to drive launch costs down. If the cost per pound lowers enough there will be an explosion in space development. A really large booster could very well help accelerate that happening.

How many large ocean-going ships ever stayed where they were assembled? A large capacity launch platform will be doing basically the same job as most really large ocean-going ships, moving large amounts of cargo from one place to another.

See, here's where my urge-to-ask-questions comes in.

We don't know because we've never tried all the options and, in fact, have not really done a good job of trying most of the options we've gone towards. But given that you have at least some atmospheric drag, structural issues, etc. I'm not sure if you can say for sure that a SeaDragon-sized or even a Saturn-sized launcher is the answer.

The thing is, expendables are OK for fewer-launches per year. But none of our other forms of transportation are really expendable. Sure, the equations a little different because you can always dissassemble whatever makes it into orbit for materials, but that will only be worth it for a certain span of time.

But, in the end, you are wasting a lot of carefully fabricated metal parts. Without even trying to, the J-2 engine ended up being quite reusable. So assuming that you can get the damn thing back on earth without too much trouble, you can reuse it.

The laws of aerodynamics actually make this even easier than you think. The denser the vehicle, the hotter the reentry. A nearly-empty rocket stage is very much not dense.

Except that it's far easier to make a parachute or other *simple* recovery system for a relatively small stage. A Saturn V is probably barely possible, but a SeaDragon doesn't feel very possible to put a parachute on that isn't a massive recovery problem. In a sense, this is one of the failings of the shuttle. It's reentry trajectory margins and ceramic thermal protection system are mostly because it has no empty fuel tanks to give it a low density.

In a sense, one of the recent projects I'm most impressed with is SpaceX because they are adding, for almost no cost in hardware, a parachute recovery option, while, at the same time, building their cost structure under the assumption that all the recovered booster will be good for is selling the charred and broken pieces for souveners a la Armadillo Aerospace -- and still being cheaper than the established players.

The F-1 Engine had a pretty horrific ISP because it was kerosene based as part of a crash program to get up to a million pound of thrust per engine pretty quick. Also Kerosene is a lot denser than hydrogen, and for that much thrust you need a LOT of hydrogen.

The Saturn was also a bit bigger than a heavy lift booster should really be. It was trying to make the Moon all in one shot. 200-ton is pushing the edge of the lift capacity of todays materials for a chemical rocket.

If America needs a heavy lift vehicle an expendable rocket about the same size as Energia (~100ton) would need to fabricated. Launched 4 times per year this would easily outstrip demand for lift. It could have put up the Entire ISS in two launches.

It would need to be associated with an American reusable people (and onl People) mover with a ~5 ton payload like the DH-1.

The Engine for the new heavy booster could be developed as a replacement for the ever-so-dodgy SRB.

F-1's are impressive, but overkill for sustained orbital or even interplanetary work.